1. Field of the Invention
The present invention relates generally to fluid supplies for vehicle occupant restraint systems and more specifically to filters for use therein and to methods of assembling those filters.
2. Description of the Prior Art
Filter assemblies for vehicle occupant restraint system fluid supplies are known in the prior art. See, for example, prior application Ser. No. 539,220 filed Jan. 8, 1975 of Applicant G. W. Goetz and R. G. Gehrig assigned to the assignee of the present invention which relates to a filter for an axial flow gas generator, and German application No. 2,325,310, filed May 18, 1973 of Shiki et al issued Dec. 6, 1975.
Certain problems have been encountered in the construction and use of such filters in fluid supplies of the cylindrical radial flow type which utilizes combustible gas generation. One problem is the tendency of the products of combustion of the gas generators to clog the filters.
Another problem encountered is that of maintaining uniform density and porosity of the filter media of the filter assembly when it is formed as a cylinder for use in a cylindrical, radial flow fluid supply.
Still another problem is the difficulty of effecting axial and radial closure of the filter assembly to prevent both movement of the filter material out of the filter assembly during assembly and/or operation of the filter and the bypassing of the filter by gas and products of combustion during operation.
Yet another problem is the high cost of construction of cylindrical filter assemblies and of assembling such assemblies into the housing of the fluid supply.